Abstract:

Mass measurements of 34Ar, 73-78Kr, and 74,76Rb were performed with the Penning-trap mass spectrometer ISOLTRAP. Very accurate QEC-values are needed for the investigations of the \(\)t-value of 0+ → 0+ nuclear β-decays used to test the standard model predictions for weak interactions. The necessary accuracy on the QEC-value requires the mass of mother and daughter nuclei to be measured with δm/m ⩽ 3 . 10-8. For most of the measured nuclides presented here this has been reached. The 34Ar mass has been measured with a relative accuracy of 1.1 . 10-8. The QEC-value of the 34Ar 0+ → 0+ decay can now be determined with an uncertainty of about 0.01%. Furthermore, 74Rb is the shortest-lived nuclide ever investigated in a Penning trap.